|
Post by racket on Apr 26, 2024 17:34:50 GMT -5
Hi Chuks
LOL.............4.7 :1 will be more than enough :-)
Excellent news about the Parts
Cheers John
|
|
richardm
Senior Member
Joined: June 2022
Posts: 268
Member is Online
|
Post by richardm on Apr 26, 2024 17:54:26 GMT -5
|
|
|
Post by racket on Apr 26, 2024 18:55:25 GMT -5
Hi Richard
Nice reading :-)
Thanks for the Link .
I'm still waiting for my battery to arrive , hopefully next week , I'm ready to go testing .
Cheers John
|
|
richardm
Senior Member
Joined: June 2022
Posts: 268
Member is Online
|
Post by richardm on Apr 27, 2024 4:58:34 GMT -5
|
|
|
Post by racket on Apr 27, 2024 17:25:20 GMT -5
Hi Richard
They make some nice stuff :-)
But we really don't need that level of flow control unless we also have variable geometry on the turbine wheel as well to be able to "match" the power requirements of the comp with any degree of efficiency .
Generally, if a turbo has NGVs in the turb scroll , they can be fixed in position once the sweet spot has been determined .
Nice big comp wheel though , had a look at some of their other videos :-)
Cheers John
|
|
|
Post by racket on May 12, 2024 1:02:02 GMT -5
Hi Guys
The new battery arrived , then the rain started :-(
Hopefully in the next few days
Cheers John
|
|
richardm
Senior Member
Joined: June 2022
Posts: 268
Member is Online
|
Post by richardm on May 12, 2024 7:32:09 GMT -5
Murphy's laws...
|
|
|
Post by racket on May 12, 2024 20:34:08 GMT -5
|
|
ripp
Veteran Member
I'm sorry, I don't speak english, so I torment you (and myself) with a translation program,Sorry
Joined: January 2013
Posts: 231
|
Post by ripp on May 13, 2024 3:30:49 GMT -5
Hi John,
the test run went wonderfully. You have a very consistent temperature curve between 1.5 and 4 bar.
What have you changed about your engine?
thanks Ralph
|
|
|
Post by racket on May 13, 2024 4:22:34 GMT -5
Hi Ralph
I opened up the jet nozzle by a few millimeters from the previous test .
Compressor efficiencies are good , but theres a lot of shaking of the test stand and chuffing from the comp , I'm refitting the IGV stator into the bellmouth with a 25 degree angle on the vanes .
I've pulled the engine outer can off and things look OK inside , I'll have a better look once its all disassembled .
Afterburner will be refitted for the next test
Cheers John
|
|
richardm
Senior Member
Joined: June 2022
Posts: 268
Member is Online
|
Post by richardm on May 13, 2024 8:39:24 GMT -5
"https://www.grc.nasa.gov/www/k-12/airplane/inleth.html" Hi John! Just watched your videos Did the new battery fix your electrical problems?
I'm wondering if your intake bell mouth has something to do with your surging problem Air hates to take a sharp turn. That makes it turbulent, meaning pressure variations at the inducer. Theses variations are then amplified by the compression ratio factor. So higher ratio higher fluctuation.. This why tou see those jet engines intake withs rounded edges and protruding quite a bit ahead of the first stage. On some jet planes ( especially earlier jets) too much of a cross wind or a slow speed side slip could induce a compressor stall and a possible flame out
But it s just my theory...
Cheers
Richard
|
|
richardm
Senior Member
Joined: June 2022
Posts: 268
Member is Online
|
Post by richardm on May 13, 2024 15:42:30 GMT -5
|
|
|
Post by racket on May 13, 2024 17:06:16 GMT -5
Hi Richard
The problem is the comp inducer angle , its too high at ~34 degrees , it wants to bite off more air than the engine can process due to limited flow through the turb stage , when you do the inlet velocity triangles theres too much incidence at the inducer , the wheel is actually doing a very good job of not going into full blown surge, it needs a much higher flowing turb stage to allow the comp to work properly , by adding my IGVs I'm simply reducing its performance potential.
The current bell mouth is a compromise , but there are other considerations influencing its use .............LOL, the main one is theres no off the shelf bell mouths for 5" inducers , then there's the matter of its strength to cope with the starter motor .
There are some pretty good Papers on bell mouths , I've read quite a few over the years whilst trying to optimise things ............ideally my engine needs a new test stand where the inlet isn't anywhere near structures , the extra flow from this engine has probably unearthed some shortcomings :-(
I'll have a read through those Papers today , theres always a "gem" to be found in every Paper :-)
Cheers John
|
|
richardm
Senior Member
Joined: June 2022
Posts: 268
Member is Online
|
Post by richardm on May 13, 2024 19:56:58 GMT -5
|
|
|
Post by racket on May 13, 2024 21:00:35 GMT -5
Hi Richard
They're nice bellmouths , too expensive though when I take in exchange rates and postage..........half a weeks income :-(
They're in alloy , I've used alloy ones before, they're a tad thin to hang my heavy/powerful starter off, I found my mountings suffered after a time , nice for leafblower starting though :-) .
Cheers John
|
|